Boiler construction



June 1o, 1930. P. MARQUAND j 1,762,180

BOILER CONSTRUCTION V Filed July e, 1928 4 sheets-sheet 2 F' .22. Xy

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s outside vthe gas pass which in boilers of and-J which, for the greaterpart of their length will he close together so as to form, asin the caseof the lirst element, narrow gas passes, insuring a h10h speed of flowfor the furnace gases contacting with these two groups. vThe rear boilerelement in this construction is conected with the front element by tubesindicated at K connecting the outer ends of the drum H with the outerends o f the drum El and lying preferably V this type is best made ofcontracting area ,5,-and 6, does not differ except in details of so asto maintain a comparatively high speed of transmission of the gaseswhich, of course, are contracting in bulk as they are cooled down bycontact with the water tubes.

The upper drums E and H are shown as connected by pipesL lying at orbelow the water level 1n the drums. and pipes M connecting with thesteam space of the drums.

I have shown as a means for delivering feed water to the lower drum aheader N extending across the top or" the flue and connected to thelower drum by a series of water tubes N1 extending across the flue andconnecting with vthe drum. H1. lThis constructiony is not my inventionbut was invented by William l. Bradford, of Wilmington, Delaware. V L

The modification illustrated in Figures 1l,

arrangement of the water tubes from the construction illustrated inFigures l, 2, and `Thertube banks in the modification of 'Figures' 4, 5,and 6, in the ends of the front section are curved soas to form a seriesof banks each made up of two rows of tubes as indicated at f, g, g1; asin the ease'of the irst described modification, I do not so curve thetwo front rows of tubes as to make them `close together but leave themspaced, as indicated at f1, f2, so that they will receive the fullradiant heat of the furnace. In the rear section of the boiler, thewater tubes are so disposed as to form six closely spaced tube banks asindicated at z', l and 2, 7', il and it O and O indicate baffles whichit is advisable to `use in connection with the boiler elements. l?, Fig. l, indicates the steam connection from the drum H to thesuper-heater vindicated at D. Q, Q, Fig. 4i,- indicate vdampers forcontrolling the iow of gases the gases contacting with the tubes andthis is the first object of my invention.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is

l. A water tube boiler element adapted for use with a one directiontransverse flow of iire gases through its tube banks comprising incombination two drums provided with tube holes spaced to leavesubstantial ligaments of sheet metal between them and one or more banksof tubes the intermediate and greater part of the length of which are ineach bank disposed parallel to each other in spaced relation whichleaves between them narrow gas passes substantially narrower than thespaces between the tube holes, said tubes having their ends spread apartand secured in the tube holes of the drums? all of the tubes in eachboiler element vin the rear of the tube rows between whichvv contractedgas passages are lirst formed being disposed as described to formcontracted gas passages throughout the entire depth of the tube banks.2. A water tube boiler element adaptedA for use with a one directiontransverse low of fire gases through its tube banks comprising incombination two drums provided on their opposite faces withsymmetricallydisposed and evenly spaced tube holes spaced to leave substantialligaments of sheet metal between them and a plurality of banks of tubesthe intermediate and greater part of the length of which are in eachbank dis-l posed parallel to each other in spaced relation which leavesbetween them narrow gas passes substantially narrower than the spacesbetween the tube holes, said tubes having their ends spread apart andsecured in the tube holes of the drums all of the tubes in each boilerelement in the rear of Vthe tube rows between which contracted gaspassages are iirst formed being disposed as described to form contractedgas passagesflm throughout the entire depth of the tube banks. Y

3. A boiler element having the features of claim l and having disposedin front of the front bank of tubes one or more rows of

